What is so different and powerful about barkcode qr code pet id tags is that the finder of your lost pet can access critical information to reunite you and your pet. and, this can be done even without a smartphone. now, in seconds and on the spot, 190 million camera phone users nationwide can retrieve as many as 6 phone numbers, email addresses, medical info and more by taking a picture of the code and mms (text) to 43588. or, the finder simply scans the code with any qr code reader. a backup url is also included. most importantly, instructions are printed on the back of every barkcode pet id tag. all tags come in 2 sizes. our standard is slightly larger than a-Quarter 1.125-Inch in diameter and perfect for pets 12-Pound and over. and our itty bitty size is great for cats, kittens and pocket pooches 0.875-Inch in diameter.